According to Patent Document 1, an exhaust manifold of an internal combustion engine, which gathers exhaust lines of three cylinders arranged in a line to one flow passage at a downstream side end, includes a first exhaust passage extending rearward along the cylinder line direction of the internal combustion engine from the cylinder located at the foremost end and leading to the downstream side end, and a plurality of second exhaust passages, respective ends of which extend from the remaining cylinders and merge together into the first exhaust passage sequentially at different points in the axial direction of the first exhaust passage. Each second exhaust passage extends from each cylinder so as to coil around the circumference of the first exhaust passage when viewed from the front of the engine and merges together with the first exhaust passage from the opposite side direction of the cylinder head side in the circumferential direction. The first exhaust passage is configured by being divided into a branch pipe at the upstream side, an intermediate pipe successively joined together at the downstream side of the branch pipe, and an outlet pipe including ends of the downstream side. In addition, the ends of the branch pipes configuring each second exhaust passage are inserted and fixed into inlets of the intermediate pipe or the outlet pipe with the ends of the branch pipes or the intermediate pipes of the first exhaust passages.